1. Field of the Invention
The present invention relates to a laminated coil component and a method for producing the same, and more particularly to a laminated coil component including a coil formed by laminating an electric conductor and a magnetic layer, and a method for producing the same.
2. Description of the Related Art
A laminated coil component is manufactured by repeating a process of laminating a number of ceramic green sheets on internal electrodes defining a portion of a coil and a process of pressurizing the upper surface of the ceramic green sheets to be temporary bonded, and, finally, pressure bonding a laminate obtained by laminating the ceramic green sheets.
However, there has been a problem with such a laminated coil component in that the internal electrodes may be horizontally shifted during the temporary bonding or final pressure bonding. Hereinafter, a description will be provided with reference to FIGS. 16 and 17. FIG. 16 is an exploded view of a laminate 202 of the laminated coil component. FIG. 17 is a view of a cross sectional structure of the laminate 202 after pressure bonding.
In FIG. 16, the laminate 202 is defined by alternately disposing ceramic green sheets 204 and internal electrodes 207. When the ceramic green sheets 204 and the internal electrodes 207 are alternately laminated as shown in the drawings, an area (hereinafter referred to as an area X) in which the internal electrodes 207 are arranged and an area (hereinafter referred to as an area Y) in which the internal electrodes 207 are not arranged, are arranged as viewed from above in the lamination direction. In such a case, the thickness in the lamination direction of the internal electrode-formed area X is greater than the thickness in the lamination direction of the non-internal electrode-formed area Y by the thickness of the internal electrodes 207.
When a difference occurs between the thickness of the internal electrode-formed area X and the thickness of the non-internal electrode-formed area Y as described above, a pressure applied to the internal electrode-formed area X is greater than that applied to the non-internal electrode-formed area Y when temporary pressure bonding or final pressure bonding of the ceramic green sheets 204 is performed. As a result, the pressure applied to the internal electrodes 207 in the internal electrode-formed area X escapes in the horizontal direction, which has caused a problem in that the internal electrodes 207 may be horizontally shifted in the laminate 202 as illustrated in FIG. 17.
Japanese Unexamined Patent Application Publication No. 6-61079 discloses a method for producing a laminated electronic component that solves the problem. FIG. 18 is a cross-sectional view of the laminated electronic component. According to the method for producing a laminated electronic component, the laminate 202 obtained by laminating a given number of the ceramic green sheets on which the internal electrode 207 has been printed is pressurized with hydrostatic pressure. Furthermore, as illustrated in FIG. 18, flatness of the upper surface and the lower surface of the laminated electronic component is secured by pressure bonding the ceramic green sheet 210 having good flexibility to the upper and lower sides of the laminate 202 using tools 211.
However, there has been a problem with the method for producing a laminated electronic component disclosed in Japanese Unexamined Patent Application Publication No. 6-61079 in that, since irregularities are formed on the upper and low surfaces of the laminate 202 due to the hydrostatic pressure press, the upper and low surfaces of the ceramic green sheet 210 need to be flattened by pressure bonding the ceramic green sheets 210 having good flexibility, and thus, the productivity of the laminated electronic component is greatly reduced.